104 
known range of the latter from 200 to 1,380 feet. Although this fauna 
does in one section actually extend a little higher than the lower fauna, it 
is not known anywhere to reach as high as the level of the upper or angio- 
spermous flora. The age of the fauna is, therefore, identical with that of 
the lower Blairmore flora, or about Aptian. The fauna is entirely of fresh- 
water origin. Although much of it is poorly preserved, the unios are in 
good condition and are very interesting. The known fauna numbers 
9 species: 
Corbula’t onestae 
Corbula? pcdliseri n. sp. 
Unio natosini n. sp. 
Unio hamili n. sp. 
Unio cf. hamili n. sp. 
Unio douglassi Stanton 
Unio sp. 
Campeloma ? sp. 
Planorhis sp. 
Ostracoda 
None of the above species has yet been found elsewhere in Canada, but 
two are present 1 in the Kootenai formation of Montana. They are Unio 
douglassi Stanton 2 and Unio natosini n. sp. Therefore, the lower 1,380 
feet or so of the Blairmore formation of the Blairmore and South Fork 
areas are to be correlated with a part of the Kootenai of Montana. The 
American Kootenai of Montana is probably equal to the Canadian Koote- 
nay plus at least a part of the Blairmore formation of the Blairmore and 
South Fork areas. The upper Blairmore flora has not yet been found 
in Montana. 
It is now possible to determine the date of several important events 
in this part of the continental interior in Blairmore time. The date of the 
first record of the appearance of dicotyledonous angiosperms in this region 
is about Aptian or Albian and the time of the first record of a fair abund- 
ance of them may be as early as Albian, i.e., late Lower Cretaceous, or as 
late as Cenomanian, i.e. earliest Upper Cretaceous. Rose has noted the 
presence of crystalline igneous pebbles in the rather persistent conglomerate 
at about 1,250 to 1,500 feet above the base of the Blairmore formation 
and their absence in the basal conglomerate of the same formation 3 . 
Schofield interprets the appearance of the igneous pebbles in the higher 
conglomerate as evidence of the unroofing of the Nelson batholith in the 
Selkirk range to the west. 4 However, it may be noted that the sandstones 
of the Blairmore formation, even in its lower part, are prevailingly 
feldspathic. 6 Whatever interpretation may be given to these igneous 
pebbles, the conglomerate holding them falls within the range of the highest 
strata containing the lower Blairmore flora and even higher and, therefore, 
is of about Aptian or Albian age, i.e. later Lower Cretaceous. If the flora 
of the Gething member to the north in Peace River canyon is younger 
than that of the Kootenay in southwest Alberta, the time of maximum 
coal deposition there was somewhat later than in the south, for the Gething 
member is that part of the Bull Head Mountain formation which contains 
most of the coal and all the thick seams. There is not now sufficient 
1 Stanton, T. W.: Personal communication. 
1 Stanton, T. W.: Proe. Am. Phi). Soc., 42, 1903, p. 195, PI. 4, figs. 3, 4. 
* Rose, B.: Geol. Surv.. Canada, Sum. itspt. 1910, p. 110 (1917). 
* Schofield, S. 1 .: Geol. Surv., Canada, Mem. 117, p. 64 (1920). 
6 Bose, B.s Personal communication. 
